<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Example12</title>
</head>
<body>
  <button>按钮1</button>
  <button>按钮2</button>
  <button>按钮3</button>
  <button>按钮4</button>
  <button>按钮5</button>
  <script>
    // 获取所有按钮元素
    var btns = document.getElementsByTagName('button');
    // 为所有按钮元素注册相同事件处理函数
    for (var i = 0; i < btns.length; i++) {
      btns[i].onclick = changeColor;
    }
    function changeColor () {
      for (var j = 0; j < btns.length; j++) {
        if (btns[j] === this) {
          // 设置当前按钮的背景颜色
          this.style.backgroundColor = 'pink';
        } else {
          // 去掉其他按钮的背景颜色
          btns[j].style.backgroundColor = '';
        }
      }
    }
  </script>
</body>
<html>